Experimental investigation of two-phase electrolysis processes: comparison with or without gravity

Derhoumi, Z.; Mandin, Philippe; Roustan, Hervé; Wüthrich, Rolf

doi:10.1007/s10800-013-0598-2

Cited by 10 publications

(7 citation statements)

References 15 publications

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“…2b ): video recordings during the experiments reveal that although the electrodes do not show noticeable differences in their hydrogen evolution behaviour in terrestrial conditions, their microgravity behaviour differs significantly: here, the evolved hydrogen gas is not released from the thin-film electrode surface and bubbles coalesce in proximity to the electrode, whereas the gas bubble release is enhanced on the nanostructured photoelectrodes. Similar observations have been made in various studies of water electrolysis in microgravity environments 9 , 15 , 22 , 23 , where the absence of buoyancy and the suppression of natural convection caused the coalescence of gas bubbles on the electrode surface and the formation of froth layers. The resulting mass transfer limitations and the increased ohmic drop in the gas bubble dispersion zone in proximity to the electrode led to a substantial decrease in current density.…”

Section: Resultssupporting

confidence: 86%

“…The catalyst micro- and nanotopography have decisive influence on the life cycle of bubbles on the surface. The growth and accumulation of bubbles on the thin-film electrode leads to a froth layer also observed in dark electrolysis experiments 9 , 15 , 22 , 23 that seriously inhibits the hydrogen evolution reaction. Figure 5a sketches the effect of lateral accumulation of gas bubbles that form a gaseous interphase which increasingly suppresses hydronium ion transport to the surface.…”

Section: Discussionmentioning

confidence: 61%

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Efficient solar hydrogen generation in microgravity environment

et al. 2018

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Long-term space missions require extra-terrestrial production of storable, renewable energy. Hydrogen is ascribed a crucial role for transportation, electrical power and oxygen generation. We demonstrate in a series of drop tower experiments that efficient direct hydrogen production can be realized photoelectrochemically in microgravity environment, providing an alternative route to existing life support technologies for space travel. The photoelectrochemical cell consists of an integrated catalyst-functionalized semiconductor system that generates hydrogen with current densities >15 mA/cm2 in the absence of buoyancy. Conditions are described adverting the resulting formation of ion transport blocking froth layers on the photoelectrodes. The current limiting factors were overcome by controlling the micro- and nanotopography of the Rh electrocatalyst using shadow nanosphere lithography. The behaviour of the applied system in terrestrial and microgravity environment is simulated using a kinetic transport model. Differences observed for varied catalyst topography are elucidated, enabling future photoelectrode designs for use in reduced gravity environments.

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Section: Resultssupporting

confidence: 86%

Section: Discussionmentioning

confidence: 61%

Efficient solar hydrogen generation in microgravity environment

et al. 2018

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“…Interestingly, a number of recent studies have eliminated the contribution of bubbleinduced convection by performing experiments in reduced gravity [37][38][39]. Mandin and coauthors have applied this technique to the electrolysis of water [37] and CuSO4 [38], and Sakuma et al [39] minimized convection in is manner in order to focus on the effect of electrode wettability.…”

Section: Bubble-induced Convectionmentioning

confidence: 99%

Natural convection effects in electrochemical systems

Novev

Compton

2018

Current Opinion in Electrochemistry

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights Recent work on natural convection in electrochemistry is reviewed.  Experimental and theoretical/simulation studies in the area are considered.  Free convection driven by concentration and/or temperature gradients is discussed.  Natural convection in systems such as electrorefining and fuel cells is covered.  A critical assessment of the concept of 'spontaneous convection' is given.

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“…Several efforts have also been made in the two-phase flow and performance analysis of electrolyzer cells [37][38][39][40][41][42][43][44]. Grigoriev et al [45] reported a two-phase mathematical model for a high pressure PEMEC.…”

Section: Introductionmentioning

confidence: 99%

Modeling of two-phase transport in proton exchange membrane electrolyzer cells for hydrogen energy

Han

Kang

et al. 2017

International Journal of Hydrogen Energy

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Multiphase transport inside a proton exchange membrane electrolyzer cell (PEMEC) plays an important role in its performance and design. Most PEMEC modeling studies so far have mainly focused on its electrochemical performance prediction and analysis, and fundamental understanding of the effect of multiphase transport on the cell performance is still lacking. In this study, a two-phase mathematical model is developed to investigate the transport properties inside liquid/gas diffusion layers (LGDLs) and to explore their effects on the PEMEC voltage and efficiency. Sudden changes in the PEMEC voltage and efficiency are captured for the first time as the current density reaches a limiting value, and the limiting current density is greatly impacted by the LGDL contact angle, porosity, and thickness. In addition, the liquid water distribution and cell performance in PEMECs with different important operating and physical parameters are examined and discussed in detail. Increasing the LGDL porosity or/and decreasing its surface contact angle will improve the PEMEC performance especially at the high current density. The thickness changes of the LGDL and membrane also have significant impacts on the cell voltage and efficiency. The model can effectively examine two-phase transport properties and provide useful information for design optimization of a PEMEC.

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Experimental investigation of two-phase electrolysis processes: comparison with or without gravity

Abstract: International audienc

Cited by 10 publications

References 15 publications

Efficient solar hydrogen generation in microgravity environment

Efficient solar hydrogen generation in microgravity environment

Natural convection effects in electrochemical systems

Modeling of two-phase transport in proton exchange membrane electrolyzer cells for hydrogen energy

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